Marangoni-driven edge-site orientation of graphite flakes for fast-charging lithium-ion battery anodes

Fast-charging performance in lithium-ion batteries is often limited by sluggish lithium-ion transport, high electrode tortuosity, and suboptimal particle orientation, particularly in graphite anodes. Additionally, conventional methods to induce tailored electrode architectures are often complex, costly, or incompatible with roll-to-roll manufacturing. In this work, we present a scalable Marangoni-flow-based slurry approach that utilizes solvent miscibility and surface tension differences to control the orientation of graphite particles during the drying phase. The edge site-oriented graphite particle alignment exhibited an overall discharge capacity of 220 mAh/g compared to a reference anode of 145 mAh/g with a percentage increase of ∼51% at a C-rate of 4C (charged in 15 min). While a specific capacity of 150 mAh/g was retained for the Marangoni-driven edge-site oriented anode compared to the reference anode of 100 mAh/g at the end of 200 cycles of 4C cycling. Additionally, the galvanostatic intermittent titration technique revealed that the Li+ diffusion coefficient at its full lithiation state of X = 1 was 3.2 × 10 −11 cm 2 s −1 , whereas the reference drops to 7.8 × 10 −12 cm 2 s −1 . The findings confirm that fluid dynamics of slurry engineering can be readily integrated into existing aqueous electrode manufacturing lines without added costs or complexity. Beyond graphite anodes, this strategy holds potential for any flake-like active material where orientation critically influences electrochemical performance.